I. Field of the Invention
The present invention relates generally to pumps and, more particularly, to pumping system and related methods involving an outer chamber and an inner chamber extending between two endplates, wherein the circumference of the inner chamber may be adjusted via a plurality of ribs and linear motors.
II. Discussion of the Prior Art
Pumps have been used for centuries, and various types of pumps have been devised, including positive displacement pumps, rotary pumps, vane pumps, and centrifugal pumps. While many of these pumps are well suited for particular uses, pumps in general do not have a high efficiency, and are not well suited for special applications, such as pumping blood or pumping sewage wastewater.
Current pumps include the crew of Archimedes that interferes with axial blood flow. Many pumps cause damage to the blood components as these blood components make either direct or near contact that surfaces of the pump. Ventricular assist pumps currently employ mechanisms to move blood that stresses the blood in some situations and are non-pulsatile.
When pumping blood, constant flow by conventional pumps may cause “pumphead” because of the sustained vasodilation. The alterations in the cellular components of the blood, typical with rotary and constant flow pumps, may be due to reactions with the vasodilated capillaries and the components of the blood reacting to this abnormal state. Ischemia may be present to the decreased lumen secondary to an accumulation of platelets and/or the blood not pulsing enough to create turbulence and transfer the gases and nutrients. This would thus be analogous to going too fast by a road sign. It may be due to the hemodynamics of fluid flow with a non-newtonian fluid. The pulse flow preferably allows for a psychological pause in the short duration dilated phase and the contraction may facilitate the movement of the blood components.
Various types of linear pumps have been devised, including linear pumps particularly intended for pumping blood. U.S. Pat. Nos. 5,676,162 and 5,879,375 disclose reciprocating pump and linear motor arrangements for pumping blood. The assembly includes a piston-valve which is placed at the inlet end of a hollow chamber. The valve leaflets may be in any arbitrary position. The pump module arrangement may occupy a space of no more than approximately 6 cm. in diameter and 7.5 cm. long. In a preferred embodiment, a quick connect locking system may be utilized, as shown in FIG. 3 of the '162 patent. FIG. 11 of the '375 patent illustrates the anatomical arrangement of a surgically implantable pump with a reciprocating piston-valve. Other patents directed to implantable pumps and or linear pumps include U.S. Pat. Nos. 5,676,651, 5,693,091, 5,722,930, and 5,758,666.
Conventional pumps have long been used to pump a slurry consisting of a fluid and a semi-solid material, which is common in sewage wastewater. Conventional wastewater pumps have significant problems due to pump plugging and abrasion, which increases repair and maintenance costs, and results in poor pump efficiency and/or short pump life.
The disadvantages of the prior art are either overcome or are reduced by the present invention, and improved linear pumps and methods of pumping fluids are hereinafter disclosed which overcome many of the disadvantages of prior art pumps, including relatively high cost of manufacture and/or poor pump efficiency.
The present invention is directed at overcoming, or at least improving upon, the disadvantages of the prior art.